Clock



FIG. 1 is a front and right side perspective view of a clock showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof, the left side view being mirror symmetrical;

FIG. 4 is a rear view thereof; and,

FIG. 5 is a top view thereof. 

The ornamental design for a clock, as shown and described. 